Improvement in sewing-machines



UNITED STATES PATENT OFFICE.

IMPROVEMENT IN SEWING-MACHINES.

Specication forming part of Letters Patent No. 118,928, dated September12, 1871.

To all whom 'it may concern:

Be it known that I, FRANCIS ELIJAH HAHN, of Philadelphia, county ofPhiladelphia, State of Pennsylvania, have invented certain Improvementsin Sewing-Machines, of which the following is a speciiication:

Myinvention consists of certain improvements in sewing-machines, toofully explained hereafter to need preliminary description, the saidimprovements having been designed with the view of producing a machineof simple and economical construction and of overcoming the effects ofwear.

Figure l, Drawing No. 1, is a vertical section of a sewing-machine withmy improvements; Fig. 2, an inverted plan view; Fig. 3, Drawing No. 2, atransverse vertical section on the line 1 2, Fig. l; Fig. 4, a plan viewof the guides for the needle and pressure-bars; Fig. 5, a verticalsection on the line 3 4, Fig. 3; Fig. 6, a sectional view of thebearings of the driving-shaft, and Fig. 7, a sectional plan, showing thefulcrum of the needle-arm.

A is the base-plate of the machine, B, the stationary arm C, theneedle-arm; D, the needlebar; E, the pressure-bar; and F, thedrivingshaft. To this driving-shaft are secured, by setscrews e e,conical sleeves a c, arranged to turn in projections b b on the underside ofthe baseplate A, so that when the driving-shaft becomes loose thesleeves may be adjusted more tightly in their bearings, and secured bythe screws after adjustment, there being in the projections or bearingsZ) elongated holes to permit the access of a suitable instrument foroperating the said screws. From a disk, G, on the driving shaft projectsa pin, f, which passes through the curved slot h on the needle-arm, thisslot being formed by and between two plates, i and i', the former ofwhich is permanently secured to the needle arm, while the plate t" issecured to the plate i by set-screws j j passing through elongated holesin the plate t', so that the plate i can be readily adjusted nearer tothe plate i when, through continued wear, the crank-pin becomes loose inthe curved slot. The conical fulcrum-pin m, Fig. 7

upon which the needle-arm turns, is adapted to and driven tightly intoconical holes formed for its reception in the stationary arm, as shown.When the needle-arm becomes loose on the pin the latter is driven backslightly, as indicated by the arrow, and is secured to the needle-arm bya set-screw, n, with which the arm is provided, the said needle-arm thenvibrating with, instead of upon, the pin, and the latter turning in theconical holes of the fixed arm. The needlebar D and pressure-bar E aresquare, and arranged, as shown in Fig. 4, so as to slide in V- shapedgrooves in the end A of the needle-arm, and the plate I secured to thesame. The looseness of needle-bars, owing to constant wear and theabsence of provisions for tightening them, is a source of much complaintb y operators of sewing-machines; by arranging square bars i'n themanner described, however, they can be readily tightened by turning theset-screws p 19, by which the plate I is secured to the stationary arm.In order to insure delicate adjustment, however, I interpose between theplate and arm two wedges, q q, which can be so adj usted as to determinethe exact distance between the plates for insuring the free movement ofthe bars without any lateral play. The needle-arm has an elongated slotfor receiving a roller on a pin projecting from the needle bar. Thepressure-bar E is made cylindrical at the upper end, which projects intoand is arranged to slide in a bar,E/, similar in shape to thepressure-bar below, but iixed between the plates H and I by a set-screw,s, as shown in Fig. 4. A spiral spring intervenes between the stationarybar E and pressure-bar E, and tends to force down the latter, which can,however, be elevated by the cam-lever J, Fig. 3. The shuttle K iscarried by a driver, L, which is arranged to slide on a bar, m, and towhich is jointed one end of a rod, u, the opposite end of which isconnected to a pin, t, rendered adjustable in a curved slot in an arm,u, which is secured to the crankpin j'. As the curved slot in this armuis eccentric as regards the crank-pin, more or less throw may beimparted to the shuttle-driver by simply adjusting the pin in the slot.I? is the feed-bar, having at its outer end the usual serrated surfaceprojecting through a slot in the work-plate of the machine. Thisfeed-bar is arranged to slide inl transverse guides on the base-plate,and carries an adjustable screw, Q, shown in Fig. 8; and between the endof this screw and a pin, zo, on the bar, projects the end of one arm ofthe lever' R, hung to a pin, w, on the under side of the base-plate, theother arm of the lever terminating in a sharp edge, y, formed bybeveling each side. A disk, T, on the driving-shaft'has two pins, c c,so situated that, as the disk revolves, one pin Will strike one lbeveledside and the other the other beveled side of the lever R, and thusimpart through the lever the desired intermittent reciprocating movementto the feedbar, and the extent of this movement Will depend upon thedistance of the end of the screW-rodQ from the pin w. Those familiarWith sewingmachines will readily understand the operation of theabove-described parts Without further eX- planation.

I claiml. The shaft F, provided with conical sleeves c, secured to andturning with, but adjustable on the shaft, in combination with thebearings b b, recessed to receive the said sleeves7 as set forth.

2. The combination, With the needle-arms7 of the plate i secured to thearm, the plate z" adjustable on the plate i, and devices for adjusting`and securing the plate after adjustment, the two plates being recessedto' form a slot, h, as set forth. A

3. The tapering pin m, having bearings in the stationary arm, incombination With the needlearm and its set-screw, so that the pin may berotated in its bearings, as and for the purpose described.

4. The shuttle-driver, connected to a rod, N, rendered adjustable on aneccentrically-slotted arm, u, secured to the crank-pin on thedrivingshaft, as set forth.

In testimony whereof I have signed my name to this specification in thepresence of tWo subscribing Witnesses.

F. E. HAHN.

Witnesses:

WM. A. STEEL, F. B. RICHARDS.

i l 1 i,

